RHD Genotyping at NYBCe

What is RHD Genotyping?

RHD genotyping is the study of the RHD gene to distinguish weak, partial, or conventional D antigen expression.

• Overcomes limitations of serologic D antigen testing

• Determines best transfusion recommendation

• Identifies candidacy for Rh immune globulin administration

When is RHD genotyping useful?

Determining Rh immune globulin (RhIG) eligibility 

• Clarifying D antigen status in patients with discrepant or weak serologic results 

Evaluation of weak D or partial D phenotypes 

• Differentiating patients who can be managed as Rh positive from those who should be treated as Rh negative 

Transfusion management 

• Determining whether Rh-negative red blood cell units are required 

Obstetric patients 

• Identifying partial antigen expression and alloimmunization risk

Complex Rh typing cases 

• Resolving serologic discrepancies or unexplained anti-D

RHD Zygosity

• Calculating risk of hemolytic disease of the fetus/newborn (HDFN) due to anti-D

RH Blood Group Expertise

Our laboratory is the leader in RH genotyping, offering deep specialization in the complex genetics of the RHD and RHCE loci. Because RH variants play a major role in alloimmunization risk, HDFN, and complex transfusion requirements, our experts provide clinically meaningful interpretation that supports safer, more informed transfusion decisions.

• Expertise in RHD zygosity, partial D, weak D, and RHCE allele variants

• Advanced resolution of serologic discrepancies

• Consultation available for challenging clinical scenarios

Key Publications on RHD Genotyping by NYBCe Authors:

• Chou ST, Jackson T, Vege S, Smith-Whitley K, Friedman DF, Westhoff CM. High prevalence of red blood cell alloimmunization in sickle cell disease despite transfusion from Rh-matched minority donors. Blood. 2013:122(6):1062-71. doi: 10.1182/blood-2013-03-490623.

• Sandler SG, Flegel WA, Westhoff CM, Denomme GA, Delaney M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD; College of American Pathologists Transfusion Medicine Resource Committee Work Group. It’s time to phase in RHD genotyping for patients with a serologic weak D phenotype. Transfusion. 2015;55(3):680-689. doi: PMID: 25438646.

• Chou ST, Westhoff CM. Application of genomics for transfusion therapy in sickle cell anemia. Blood Cells Mol Dis. 2017;67:148-154. PMID: 28827079.

• Chou ST, Evans P, Vege S, Coleman SL, Friedman DF, Keller M, Westhoff CM. RH genotype matching for transfusion support in sickle cell disease. Blood. 2018;132(11):1198-1207. doi: 10.1182/blood-2018-05-851360.

• Westhoff CM, Nance S, Lomas-Francis C, Keller M, Chou ST. Experience with RHD*weak D type 4.0 in the USA. Blood Transfus. 2019;17(2):91-93. PMID: 30036180.

• Flegel WA, Denomme GA, Queenan JT, Johnson ST, Keller MA, Westhoff CM, Katz LM, Delaney M, Vassallo RR, Simon CD, Sandler SG. It’s time to phase out “serologic weak D phenotype” and resolve D types with RHD genotyping including weak D type 4.Transfusion. 2020;60(4):855-859. PMID: 32163599.

• Chou ST, Mewha J, Friedman DF, Mlkvy J, Hue-Roy K, Ochoa G, Vege S, Westhoff CM. Real-world feasibility of RH genotype-matched red blood cells for chronically transfused patients with sickle cell disease. Blood 2023;142(S1):1291.

• Chou ST, Mewha J, Friedman DF, Lazariu V, Makrm S, Ochoa G, Vege S, Westhoff CM. Genotyped RHD+ red cells for D-positive patients with sickle cell disease with conventional RHD and unexpected anti-D.Blood. 2024;144(19):2045-2049. 

See more publications on red cell genotyping by NYBCe authors.